Effects of cordycepin on RNA synthesis in Physarum polycephalum

Fouquet, H.; Wick, R.; Böhme, Roswita; Hw, Sauer

doi:10.1016/0003-9861(75)90251-9

Cited by 22 publications

(7 citation statements)

References 24 publications

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“…Hydroxyurea was used at 50mM [27] or at 1 mM [28], as a SO-fold concentrated stock solution in water, filter-sterilized, with a 30-min pre-incubation. Cordycepin (3'-deoxyadenosine) was oadded from a 25-fold concentrated stock solution in 25/0 ethanol and was used at 200 pg/ml (except when noted) [29] during the 60-min preincubation and during the labeling. All stock solutions were sterilized by filtration.…”

Section: Labeling Of Physarummentioning

confidence: 99%

Patterns of histone acetylation in Physarum polycephalum

Waterborg

Matthews

1984

European Journal of Biochemistry

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Histone acetylation has previously been correlated with both chromosome replication and transcription. We present evidence that (a) confirms both correlations in the true slime mold, Physarumpolycephalum and (b) shows that quite a different pattern of acetate turnover is associated with replication compared with transcription. The pattern asssociated with replication involves turnover of acetate on all four core histones on species containing one or two acetates per molecule. This pattern was resolved from the transcription-associated pattern by three different procedures : (a) detailed analysis of gels of histones pulse-labelled with acetate; (b) the pattern of acetylation of histones pulse-labelled with [3H]lysine; and (c) the pattern of acetylation of soluble histones. The pattern associated with transcription is restricted to histones H3 and H4 and occurs mostly on highly acetylated species. This pattern was resolved by (a) analysis of gels of histones pulse-labelled with acetate; (b) the pattern of histone acetylation in G2 phase of the cell cycle; and (c) the pattern of histone acetylation in the presence of cycloheximide.

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Section: Labeling Of Physarummentioning

confidence: 99%

Patterns of histone acetylation in Physarum polycephalum

Waterborg

Matthews

1984

European Journal of Biochemistry

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“…It could be, therefore, that the stimulatory factor, which is sensitive to salt, might be active on those RNA polymerase molecules which are transcribing in isolated S-phase nuclei. We have previously provided some evidence that transcription of poly(A)-RNA in early S phase in Physarum is coupled with DNA replication [14,24] and we now postulate that the intensive and moderate mRNA transcription in S phase and GZ phase respectively and lack of mRNA synthesis in spherules are due to the fluctuations of the nuclear elongation factor described in this paper. Its mechanism in vivo might be an activation of resting RNA polymerase B molecules that have attached in a pre-initiated state to chromatin during S phase of the mitotic cycle from a reservoir of abundant free RNA polymerase molecules present in Physarum [6].…”

Section: Discussionmentioning

confidence: 55%

“…RNA synthesized in vitro on native DNA with RNA polymerase B from Physarum with or without the factor was extracted by a modified phenol method [24]. Purified carrier RNA from yeast (100 yg/ml) was added and RNA was precipitated overnight at -20 "C by 2.5 vol ethanol.…”

Section: Nucleic Acid Extractionsmentioning

confidence: 99%

A Nuclear Elongation Factor of Transcription from Physarum polycephalum in vitro

Ernst

Sauer

1977

European Journal of Biochemistry

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Homogenates of Physarum plasmodia contain a factor which stimulates UMP incorporation on native DNA by solubilized homologous RNA polymerases in vitro. The factor is a heat-sensitive protein and has been located in nuclei. It does not alter the template activity of DNA nor the initiation frequency of transcription. The factor interacts with free or bound RNA polymerase molecules (only at 37 "C and at low ionic strength) and yields larger transcripts in vitro.The level of the factor in vitro fluctuates: it is gradually reduced during spherulation and reaches its maximum in mid S phase of the cell cycle of Physurum.There is convincing evidence for multiple RNA polymerases in eucaryotic cells [ 11. RNA polymerases A and B have been characterized in the myxomycete Physarum [2-41. An independent regulation of these two enzymes as well as a correlation of the activity levels with RNA synthesis in vivo has been demonstrated during differentiation [5], but not during the cell cycle [6].Since the discovery of the sigma [7] factor, which plays a role in proper initiation of transcription by Escherichia coli RNA polymerase, similar factors have been postulated in eucaryotic cells. Stimulatory factors are present in yeast [8] as well as in plant [9] and animal cells [lo, 111. However, most factors do not interfere with the initiation process of transcription, and some studies clearly indicate that the stimulation of UMP incorporation into RNA by a factor from rat liver is due to an increased elongation rate [12]. In no case known to us has a correlation been observed between RNA synthesis in vivo under distinct physiological conditions and a factor which stimulates transcription in vitro.We wish to report evidence for an elongation factor in Physarum and its fluctuations in the life cycle of this myxomycete, from a maximum in S phase of the cell cycle to complete absence in encysted plasmodia.

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“…The stimulation does not occur if DNA replication is impaired by cytosine arabinoside. The observation that polymerase B is preferentially active in replicating nuclei of Physarum also suggests a connection between transcription and DNA replication [47,48].…”

Section: Discussionmentioning

confidence: 99%

On the Initiation of Mammalian RNA Polymerase at Single-Strand Breaks in DNA

Dreyer

Hausen

1976

Eur J Biochem

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Mammalian RNA polymerase B is able to initiate at single-strand breaks in the DNA template. A 3'-OH end at a nick is required for initiation whereas the 5'-end may be either -OH or phosphate. The 3'-OH group does not function as a primer. An appreciable part of the newly synthesized RNA started at a nick remains associated with the DNA in hydrid form. Initiation of exogeneous RNA polymerase B on chromatin exhibits similar requirements.The recognition of initiation sites on the DNA by RNA polymerase poses a major problem for the understanding of the process of transcription. Intact mammalian DNA is a poor template for mammalian polymerase B [2] (for a review see [I]). Treatment of the DNA with DNAase I greatly improves its template activity [3].Since mammalian RNA polymerase B is known to attach preferentially to single-stranded DNA [4,5] it is possible that the increased activity of DNAasetreated DNA results from the generation of singlestranded regions. Permanent single-stranded regions could arise from extensive degradation or, alternatively, transitory single-stranded regions could arise opposite single-strand breaks (nicks) by partial or temporary destabilization of double-stranded structure [6,7]. Such a destabilization may also facilitate strand separation required for the initiation process A third possibility is that the polymerase recognizes the free ends at an internal nick. It may then be possible that a specific configuratiori at the nick site is required for the initiation event.We have investigated this question by studying the effect on the template activity of modifications of the DNA by different enzymic treatments. Methods used to modify the DNA are outlined in Table 1. As can be seen these methods allow the preparation of DNA samples containing single-strand nicks with different chemical structures.

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Effects of cordycepin on RNA synthesis in Physarum polycephalum

Cited by 22 publications

References 24 publications

Patterns of histone acetylation in Physarum polycephalum

Patterns of histone acetylation in Physarum polycephalum

A Nuclear Elongation Factor of Transcription from Physarum polycephalum in vitro

On the Initiation of Mammalian RNA Polymerase at Single-Strand Breaks in DNA

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